<header id="header" class="header">
    <div class="logo"><a href="javascript:;" title="慢慢买"><img src="./img/header_logo.png"></a></div>
    <div class="appdown"><a href="javascript:;" title="手机app下载"><img src="./img/header_app.png" alt="手机app下载"></a>
    </div>
</header>